JPS5922656B2 - Coating cutting equipment for continuous production of plastic coated metal tubes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for cutting plastic coatings during continuous production of plastic-coated metal tubes.

In recent years, plastic-coated steel pipes, in which the outer surface of the steel pipe is coated with plastic, have been widely used for gas transportation steel pipes, water supply steel pipes, steel piles, etc. due to their excellent anti-corrosion performance.

The main methods of coating plastic coatings are to coat the entire circumference of the tube using a round die from a plastic extruder, or to extrude a strip of plastic using a T-shaped die and apply it onto a rotating tube. A winding method (hereinafter referred to as the T-die method) has been implemented.

This T-die method does not require replacing the die depending on the size of the pipe diameter, and has been adopted as a coating method particularly suitable for large-diameter pipes. , JP-A-48-38373 and JP-A-50-2072 have been proposed. This T-die method has the advantage of being able to coat any pipe regardless of its diameter, but it has the disadvantage that it is difficult to coat metal pipes continuously and is therefore inferior to the round die method in terms of efficiency. It was hot. Conventionally, a method for continuously manufacturing plastic-coated metal tubes has been proposed as a method for solving these drawbacks, and FIG. 1 shows a schematic plan view of an apparatus for carrying out this method.

As shown in the figure, 1 is a leading metal tube, and 1 is a trailing metal tube, and a pair of rotary transfer rolls 2 each having a substantially horizontal axis obliquely intersecting the axial direction of the metal tubes 1 and 2, It is rotatably attached to a support stand 3 extending in a direction perpendicular to the axis of the roll 2, and the support stand 3Vc is a drive device 2a that rotationally drives one of the rolls 2 of the pair of rotary transfer rolls 2. are attached to constitute a roll-type rotary transfer device 4, and a large number of rotary transfer devices 4 configured in this way are arranged at predetermined intervals in the tube axis direction of the 11 metal tubes. The metal tubes 1 and 2 are placed on each roll 2 in the rotary transfer device 4, and are transferred in the direction of the tube axis while being rotated about the tube axis. Also shown in FIG. 1 is a plastic coating, in which between two adjacent rotary transfer devices 4 a preheated leading metal tube 1 is first coated with an undercoating agent and then half-filled. The molten plastic strip is wrapped and crimped, then cooled to form a beautiful plastic coating on its surface.

5 is a preheater for preheating the preceding metal tube 1, which is provided below the preceding metal tube 1; 6 is a preheating panner for applying an undercoating agent such as an adhesive to the preheated preceding metal tube 1; A coating device 7 is an extruder installed close to the preceding metal tube 1, and a semi-molten plastic strip 8 is extruded from a T-die 7a of the extruder 7, and the undercoating agent is applied thereto. The semi-molten plastic strip 8 is wound around the preceding metal tube 1 in a partially overlapping manner.

Reference numeral 9 denotes a pressure roll provided below the preceding metal tube 1, which presses the semi-molten plastic strip 8 wrapped around the preceding metal tube 1 against the preceding metal tube 1 with a predetermined pressure. ing.

Thereafter, the plastic coating coated on the preceding metal tube 1 which has passed through the pressure roll 9 is further cooled. Furthermore, FIG. 1 shows a general method for transporting metal tubes without using a trolley, in which a trailing metal tube 1'' is arranged in series with a leading metal tube 1, and the tube end is are in contact with each other, or the T-die 7a of the extruder 7
The trailing metal tube 1 is arranged so that the distance between the tube ends is shorter than the width of the semi-molten plastic strip 8 to be extruded from the metal tube 1, and the rotating transfer roll 2 causes the trailing metal tube 1' to rotate at the same rotational speed and speed as the leading metal tube 1. Even after the preceding metal tube 1 is rotated and transferred at a constant transfer speed, the plastic coating continues to be applied to the trailing metal tube 1'' without interrupting the coating operation.

The leading metal tube 1 after being coated with plastic is continuously connected to the trailing metal tube 1, which is still in the middle of the plastic coating, by the cooled plastic coating, and between the tube ends of the two metal tubes 1 and V. By cutting the coating, the leading metal tube 1 is separated from the trailing metal tube 1'' and transported to the outside.

Furthermore, the plastic-coated metal pipes carried outside are
That if necessary? The plastic coating is cut to form an uncoated portion of the plastic coating over a predetermined width.
Therefore, the conventional cutting work involves cutting the plastic-coated metal pipe from the plastic-coated metal pipe (pipe transfer line) to separate it from the metal pipe that is still in the plastic-coating process and transporting it to the outside. Accordingly, the metal tube must be separated into two operations: cutting to form an uncoated portion at the end of the metal tube after being carried out, which has the disadvantage of extremely low work efficiency.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems.In an apparatus for cutting a plastic film coated on a metal tube that is continuously conveyed by rotation, the adjacent end of the metal tube that is continuously conveyed is The plastic coating of the part,
A pair of cutters arranged parallel to each other at a predetermined distance are attached to a cart to cut so as to form an uncoated portion each having a predetermined width, and adjacent ends of the continuous metal pipe are detected. Cutting by the cutter is started manually by operating a detection device or by visually detecting the adjacent end, and the cutting is performed by the rotation of the metal tube, and the cart is adjusted to the speed at which the metal tube advances. The present invention is characterized by a coating cutting device for continuous production of plastic-coated metal tubes, which performs coating cutting in synchronization.

The present invention will be explained below with reference to examples and drawings.

FIG. 2 is a front view of the apparatus of the present invention, FIG. 3 is a side view showing the same part, and FIG. 4 is a diagram showing the arrangement of a portion of the cutter.

As shown in the figure, 11 is a metal tube, and 12 is a continuous manufacturing apparatus for plastic-coated metal tubes as described above.
In order to rotate and transfer the metal tube 11, the metal tube 1
A pair of rotary transfer rolls are arranged at a predetermined interval in the transfer direction of the metal tube 11, and the outer periphery of the metal tube 11 is coated with a plastic coating before reaching the coating cutting device described later. It is becoming more and more common.

Reference numeral 13 denotes a traveling trolley installed between the rotary transfer devices so as to be movable back and forth along the transfer direction of the metal tube 11.
It is placed on a rail 16 of a base 15 provided along the transfer direction.

17 is a drive device (motor) attached to the traveling trolley 13 for moving the traveling trolley 13,
A control device, which will be described later, causes the traveling cart 13 to travel at the same speed as the metal tube 11 during coating cutting, and to move it to a predetermined standby position after cutting is completed.

A support frame 18 is provided opposite to the traveling truck 13, and a rotary body 19 is rotatably attached to the support frame 18. cutters (disc cutters) 20 are arranged in parallel.

A rod 21a of a cylinder 21 provided on the traveling carriage 13 is connected to the rotating end of the rotating body 19, and the rotating body 19 rotates due to the operation of the cylinder 21, thereby rotating the cutter 20. It is pressed against the metal tube 11 being transferred and starts cutting the plastic coating coated on the metal tube 11. Hey, the above Katsuta 2
0 is attached to the support rod 23, and the support rod 2
3 is slidably fitted into a support tube 24 attached to the rotary body 19, and the cutter 20 is connected to the metal tube 1 by a spring 25 fitted to the rod 23.
It is designed to receive force in the direction of pressing 1. Reference numeral 22 denotes a detection device for detecting the adjacent end of the metal tube 11 that is continuously transferred, and is composed of known means such as a current flaw detection device and a proximity switch, and is attached to the rotating body 19. ing.

Then, based on the adjacent end detection signal of the continuous metal tube 11 of the detection device 22, an appropriate control device (not shown) is activated.
The cylinder 21 is started to operate via the cutter 20, and the cutter 20 starts cutting the coating.
Note that the detection device 22 is not the rotating body 19, but
It may be installed at an appropriate position on the traveling vehicle 13, and detects the adjacent ends of the continuous metal pipes 11 and receives the detection signal;
The timing for starting coating cutting can be determined by the control device based on a predetermined relationship. Further, if the coating at the adjacent end of the metal tube is recessed and the location can be visually detected, the cutter can be manually set without using a detection device for the adjacent end.

That is, the part corresponding to the detection end of the detection device is made into a wedge shape, and by manually inserting the wedge into the recess of the adjacent end, the cutter is caused to follow the rotational movement of the tube in the same manner as described above. A simple method such as sending the information can also be used. Further, the pair of rotary transfer rolls 12 of the rotary transfer device is arranged such that the distance between the opposing rolls is changed according to the diameter of the metal tube 11 placed thereon. Even if the diameter changes, the position of the lower end outer circumferential portion of the metal tube 11 remains almost constant without moving up or down depending on the tube diameter, only by changing the interval between the rolls, so the cutting position by the cutter 20 is It remains almost constant regardless of the diameter of the metal tube 11.

With this configuration, it is possible to cut the coating of the metal tube 11 coated with the plastic coating and continuously transported so as to form an uncoated part over a predetermined width at the adjacent end thereof. First, the traveling cart 13 is placed on standby at a predetermined standby position for starting coating cutting, and the detecting device 22 detects the adjacent end of the plastic-coated metal tube 11 that is being continuously transported.

Based on the detection signal from the detection device 22, the cylinder 21 is actuated via the control device to press the cutter 20 against the outer periphery of the metal tube 11 to start cutting the plastic coating, and the drive device 17 is actuated. Then, the traveling cart 13 is moved in synchronization with the transfer speed of the metal tube 11. By doing this, the cutter 20 is fixed against the rotation of the metal tube 11, so that the cutter 20 is fixed against the rotation of the metal tube 11.
1, the plastic coating of the metal tube 11 is cut over its entire circumference. In this way, an uncoated portion of the plastic film is formed on the end portion of the metal tube 11, but the cutting is performed so that the adjacent end of the continuously transferred metal tube 11 is cut by the pair of cutters 2.
By starting when the process reaches the center of 0, the widths of the uncoated portions at the rear end of the leading metal tube and the tip of the trailing metal tube can be made equal. After cutting the coating, the cutter 20 is separated from the outer peripheral surface of the metal tube 11, and the drive device 17 is operated to move the traveling truck 13 backward.
is moved to a predetermined standby position for starting to cut the coating.

As explained above, in this invention, as a result of being able to simultaneously form the uncoated portions of the rear end portion of the leading metal tube and the tip portion of the trailing metal tube, it is possible to separate the two metal tubes for carrying out the leading metal tube to the outside. can also be carried out, significantly improving work efficiency.

Since the coating can be cut while being left to the rotation of the metal tube,
It can be easily performed without requiring any special equipment.

[Brief explanation of drawings]

Fig. 1 is a schematic plan view of a continuous manufacturing apparatus for plastic-coated metal tubes, Fig. 2 is a front view of the inventive apparatus, Fig. 3 is a side view showing the same part, and Fig. 4 is a diagram of the arrangement of a part of the cutter. It is. 1, 11...Metal tube, 2,12...Rotary transfer roll, 3...Support stand, 4...Rotary transfer device, 5...
... Preheating burner, 6... Coating device, 7... Extruder,
7a...T-die, 8...Semi-melting plastic strip, 9...Crimping roll, 13...Traveling trolley, 14...
・Wheel, 15... Base, 16... Rail, 17...
・Drive device, 8... Support 1 frame, 19... Rotating body, 2
0... cutter 1... cylinder, 22... detection device.

Claims (1)

[Claims] 1. In an apparatus for cutting a plastic coating coated on a metal tube that is continuously transferred by rotation, an uncoated portion is formed over a predetermined width of each of the plastic coatings at adjacent ends of the metal tube that is continuously transferred. A pair of cutters arranged parallel to each other at a predetermined interval are attached to a cart to cut the continuous metal tube in such a manner that the adjacent ends are The cutter is visually detected and manually started to cut, and the cutting is performed while the metal tube is rotated and the cart is synchronized with the speed of movement of the metal tube. Coating cutting equipment for continuous production of plastic coated metal pipes.